<html>
	<head>
		<title>JavaScript Math sqrt() Method</title>
	</head>
	<body>
		<script type="text/javascript">
			var value = Math.pow(8,0.5);
			console.log(value)


			var value = Math.sqrt(8);
			console.log(value)

			var value = Math.sqrt(81);
			document.write("<br />Second Test Value : " + value);

			var value = Math.sqrt(13);
			document.write("<br />Third Test Value : " + value);

			var value = Math.sqrt(-4); //如果数的值是负的，开方返回NaN
			document.write("<br />Fourth Test Value : " + value);
		</script>
	</body>
</html>
